OpenEuphoria

Re: Error Handling

• Posted by Igor Kachan <kinz at peterlink.ru> Mar 19, 2001
• 628 views

David Cuny wrote:

 > to be lazy (like me), you could just put a single
 > recovery routine in the
 > top level procedure:
 >
 >    procedure main()
 >       -- code goes here
 >
 >    on error do
 >       -- save the data file and shut down
 >
 >    end procedure
 >
 > Comments?

Similar "on error goto" statement was useful
for me (almost just and only) when I didn't
know what was wrong in my algorithms realised 
in the QB programs and I wanted to go some
steps more in the job without immediate hard
corrections.

The second and last kind of these things was running
the program on the unknown machine - for example,
automated selection of the right graphics mode with
*statement* not *function*  SCREEN like this:

'-------basic code
on error goto 911
SCREEN 13 'if there is no this mode on machine,
          ' error,jump to 911 mark
          'if there is this mode on machine,
          ' no error, jump to 912 mark
goto 912
911
SCREEN 1
912
'-------end of basic code

But there are no standard *functions* like

i = graphics_mode(257)
or
i = open ("file", "wb")

in that basics, same as other robust
Euphoria features for debugging and
running robust programs on any machine.

Basics (and other *slangs* - sorry, just
a bad but innocent sailor's joke  just use
primitive universal statement "on error goto"
instead of Euphoria's concrete powerful
functions.

Basics *allow* errors and stop program
in that places where Euphoria's function
just returnes -1 or 0.

What an ERROR exactly?

Do you khow ?

Or you don't want to know ?

If *you* don't know then what
will do *your program*?

The *next* error instead recovery
under your *unknown* commands
and so on?

And how long time ?

Well, if you know -- then why does
this bug sit in your program ?

Do you see - questions, not answers ?

But there may be two useful things:
first - under DOS, when compiled Eu2C
program runs with trace, *on real crash*
not *exit on error*, for safely *closing*
without damage of ctrace.out file when
ctrl+alt+del (or Reset button - he he he)
struck -- but only for program debugging
with Beta translator on plain DOS
and Beta translator debugging.   :-{)

Second - to save, not delete,
the swap file on running off memory
under plain DOS to see the content
and the size of this file for
more information about bug, same
may be about more wide data
dumping in ex.err, on each error,
when hypothetical "with_wide_data_dump"
option is selected in the main
program file.

David knows what data he wants to save,
yes David?

But the first thing is the OS's, and BIOS's,
and machine's duty, not Euphoria's, while the
second one may be a pure Euphoria's duty.

I am *very lazy* programmer (see contrib.htm
on the RDS site) and I don't want at all
"on error do" in Euphoria, because of I know 
that I must to know my program as well as
I can know *my* program, and Euphoria, just
without ON ERROR DO or GOTO, only helps me
to make my programs well documented, debugged
and robust ones.

Yes, I am lazy, but I don't want the old and
white bugs each behind of each "on error"
statement in my program or all behind the
single "on error" statement in the main
procedure.
And Euphoria works for me and helps me.

We all just don't know or don't uderstand or
don't use or don't remember well enough
Euphoria's simple power sometimes, I think. No ?

Regards,
Igor Kachan
kinz at peterlink.ru